Two questions that may be related

ConstantVigilance

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Just finished skimming over the other thread. Looks like this has been going on for a little while but I'll try and contribute if I can.

First off, yes: Too much timing advance can kill glow plugs. Individual experience seems to vary, which is why some are still skeptical of this possibility.

Overly advanced timing causes a more violent shockwave in the combustion chamber because the piston is still travelling up when the flame front hits the piston crown. This is not unlike a pre-ignition knock found in a gasser when the timing is too advanced, or fuel octane is too low. Timing needs to be at a certain point for a reason. This is true for gassers or diesels.

This abnormal shockwave causes more MECHANICAL stress on the glow plugs. Damage can occur without any electric current flowing through the glow plugs. I have personally lost glow plugs to this in the past (though not an entire set).

As one can imagine, this will also cause more mechanical damage on the other internal components of the engine. Rings, pistons, wrist pins, conrods and mains... they all take a hammering when timing is excessively advanced.

If the engine seems to run well where it is, don't be so easily fooled. Believe it or not, you can actually get an IDI to run with the IP turned 180 degrees off. Not well, but it will run. Getting it to seem about right with 1 tooth off is not impossible.


Ok, smoke analysis:

VERY subjective. However more advance will not necessarily mean less smoke. Too much advance and it will smoke plenty at idle. Same with too little. Mine had a slight gray haze at operating temperature when it was slightly too advanced. It's also entirely possible that a single bad injector could be dripping enough to completely overshadow any smoke effects from a timing error.


Engine power:

Also VERY subjective. My truck seems to "pull back" slightly when the high idle/cold advance shuts off while driving. That doesn't mean the truck should be running the higher advance all the time. There are other interactions happening in the fuel system that make it seems like you are losing power with less advance. Please don't get fooled into thinking more advance is always good. You must know where your timing is first before adding more or less.


Timing by ear:

Not generally recommended, but a shop with the right tools is not always available. The following assumes the cold advance/high idle are working correctly. Make the adjustment so that there is a noticeable (but not excessive) ignition knock when timing advance is on.
It should sound almost like a 7.3 powerstroke. When the timing advance turns off, the high pitched knock should go away. Also, the knock should not become a loud crackle when pulling hard under load and at higher RPMs. If you're still getting that powerstroke knock under load (with cold advance off), you are probably still a bit too advanced.

Again, I don't recommend timing by ear especially with an unknown engine history, but this should get you close enough until a proper timing can be arranged.
Thank you so much for the effort you put into the response. It's extremely helpful

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Joseph Davis

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line up number one cylinder on timing mark; make sure it is compression stroke. take out number one injector; and take off front cover to injection pump and check marks. you can use a really long straw to make sure the piston is at top dead center. but I would also take out all the glow plugs so the cylinders don't build any compression and crank by hand and find top dead center. That will check your crank mark and check pump mark and it will still thump the pipe about -10 to +10 degrees before or after TDC then mark pulley. if the cam gear is off you can check it by turning it and look to see when exhausts valve starts to opens mark it closes mark it and measure it with a degree wheel then check intake same way. Then look it up. But if I thought it was a tooth off on Crank to Cam I would just tear it apart an fix it. But odds are the pump timing is off. From reading all the post for the past few month all these guy Know what they are talking about. I always ask them because they have been doing this for a long time and this is my first diesel in picture. I just finally bought a timing meter because all the noise a diesel make, I want to know my timing is off before I tear it apart. Using proper diagnostic equipment is important to me because I learn from it and then I can apply it in the future. I am not afraid of doing something but when in doubt ask Oil Burners because they have already been there and have already done that. I hope you figure it out Good Luck
 

ConstantVigilance

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line up number one cylinder on timing mark; make sure it is compression stroke. take out number one injector; and take off front cover to injection pump and check marks. you can use a really long straw to make sure the piston is at top dead center. but I would also take out all the glow plugs so the cylinders don't build any compression and crank by hand and find top dead center. That will check your crank mark and check pump mark and it will still thump the pipe about -10 to +10 degrees before or after TDC then mark pulley. if the cam gear is off you can check it by turning it and look to see when exhausts valve starts to opens mark it closes mark it and measure it with a degree wheel then check intake same way. Then look it up. But if I thought it was a tooth off on Crank to Cam I would just tear it apart an fix it. But odds are the pump timing is off. From reading all the post for the past few month all these guy Know what they are talking about. I always ask them because they have been doing this for a long time and this is my first diesel in picture. I just finally bought a timing meter because all the noise a diesel make, I want to know my timing is off before I tear it apart. Using proper diagnostic equipment is important to me because I learn from it and then I can apply it in the future. I am not afraid of doing something but when in doubt ask Oil Burners because they have already been there and have already done that. I hope you figure it out Good Luck
Thanks for your reply. Your absolutely right. A ton knowledge on here. I've built this rig from the frame up, and only have had to post a few times. 99% of the time, when I've had a problem, I've found the solution on here.



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Macrobb

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The other thing you might want to try is take a ZD-9 glow plug, heat it up a couple of times with a wire. Get it hot, let it cool, get it hot again, let it cool, then install it.
Then see what happens.

It shouldn't apply to zd-9s, but I saw an informative presentation about cheaper glow plugs and why they swell - the packing material inside the glow plug may not be fully water-free, and that water expands when heated up. If your ZD-9s have the same issue(manufacturing problem), a couple of slow heat cycles would show it or at least let any moisture out via the seal at the top, before exposing it to the harsh conditions of your engine).

I know I actually proved this 'theory' with a champion plug - heated it up quickly right out of the package and actually had it bulge a little. I ended up actually using it, and it worked fine for a while anyway. Not sure if it was replaced or is still in there.

The other thing to think about is injector issues - If the injectors on the cylinders that keep blowing are leaking, you'll be getting hot fuel dripping out at the wrong time and causing issues. Is it an issue with all the cylinders, or just the front two?
 

riotwarrior

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...... you can use a really long straw to make sure the piston is at top dead center.....
Please explain this in great detail

Please explain this in great detail

Please explain this in great detail


Not happening....

Not possible...

JM7.3CWEh!......maybe u have special ju ju though.
 

ConstantVigilance

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The other thing you might want to try is take a ZD-9 glow plug, heat it up a couple of times with a wire. Get it hot, let it cool, get it hot again, let it cool, then install it.
Then see what happens.

It shouldn't apply to zd-9s, but I saw an informative presentation about cheaper glow plugs and why they swell - the packing material inside the glow plug may not be fully water-free, and that water expands when heated up. If your ZD-9s have the same issue(manufacturing problem), a couple of slow heat cycles would show it or at least let any moisture out via the seal at the top, before exposing it to the harsh conditions of your engine).

I know I actually proved this 'theory' with a champion plug - heated it up quickly right out of the package and actually had it bulge a little. I ended up actually using it, and it worked fine for a while anyway. Not sure if it was replaced or is still in there.

The other thing to think about is injector issues - If the injectors on the cylinders that keep blowing are leaking, you'll be getting hot fuel dripping out at the wrong time and causing issues. Is it an issue with all the cylinders, or just the front two?
Thank you for the response.

It's happening on all the cylinders. I burned up a complete set and then replaced them thinking that I overused my push button glow plug bypass. But then decided to unplug the entire harness and drive it like that for a little while. Then discovered that I burned up that set as well. These are all Motorcraft plugs. That's when I started putting one plug in at a time and adjusting timing. I burned up three plugs doing this little experiment.

I think the most important thing is to have it time to properly. I contacted a member on this forum and just waiting to hear back.



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david85

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Please explain this in great detail

Please explain this in great detail

Please explain this in great detail


Not happening....

Not possible...

JM7.3CWEh!......maybe u have special ju ju though.

Yeah, that one's a head scratcher for me too LOL

I'm not sure how you could access the top of the piston by going in through the prechamber (injector and glow plug are in the prechamber). On a gasser you can pull a spark plug. On a direct injected diesel, you could pull an injector. But this is an IDI we're dealing with here.

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DrCharles

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From looking at pictures of the block side of IDI heads, wouldn't it still be possible to put a long thin wire through one of the holes (GP or injector) down into the combustion chamber? I haven't tried myself, just asking... :dunno
 

ConstantVigilance

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Well thats kinda flat....here I was hoping u had some ju ju I could learn.....albeit...bizzaro ju ju but new ju ju nome the less....kinda anti climatic ....
Also, I'm going to assume that because of pre cup design, clearance issues shouldn't be the cause of burning out my glow plugs.

That is to say, the Piston can't reach the plug. From the look of the picture, it wouldn't make a difference if the block had been decked.

From what I understand, if the block was decked there would be valve clearances.



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Thewespaul

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That is correct, only thing they could possibly affect the gps that way is if the combustion ratio had been raised by decking the block and the higher cylinder pressures cause the plugs to fail, but that is a stretch
 

ConstantVigilance

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That is correct, only thing they could possibly affect the gps that way is if the combustion ratio had been raised by decking the block and the higher cylinder pressures cause the plugs to fail, but that is a stretch
Thanks. I've start a conversation with a diesel mechanic in my hometown. I'll know more about what he thinks tomorrow. But he doesn't have the proper tools to time this truck.

And as everyone has said on this forum, he claims he can do it by ear better than the tool.

He claims he "cut his teeth" on these engines working for Ford back in the day. But, I'm pretty sure he forgot about the pre cup design. Makes me a little leery.


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